Among typical types of electric motor, there is a motor which includes a seal portion for sealing a gap between members configuring an outer frame of the motor. For example, Japanese Patent Application Publication No. 2014-110697 discloses an electric motor which includes a brush holder in which a seal portion made of rubber is installed. With the seal portion, the brush holder is held by a yoke and a bracket. This electric motor may be configured to prevent water from being infiltrated into the motor by the seal portion, such that the electric motor may be used outdoors such as on a vehicle and the like.
In the electric motor as described above, the seal portion is sandwiched between the yoke and the bracket as well as the brush holder (brush card) and the yoke (housing). In this case, an axial dimension between the brush holder and the yoke, and an axial dimension between the yoke and the bracket may be easily changed due to a dimensional error entailed in the elements or the assembly thereof. Therefore, when the axial dimension of the seal portion is uniform, both of the gap between the brush holder and the yoke and the gap between the yoke and the bracket may not be sufficiently sealed and waterproof property of the electric motor may be degraded.
In relation to this structure, for example, if a shape of a portion sandwiched between the brush holder and the yoke in the seal portion and a shape of a portion sandwiched between the yoke and the bracket are different from each other, it is easy to very appropriately seal both of the gap between the brush holder and the yoke and the gap between the yoke and the bracket. In this case, however, in the seal portion, there is a need to make the portion sandwiched between the brush holder and the yoke thin, the portion sandwiched between the yoke and the bracket thick, etc. Due to the shape of the seal portion as described above, the axial dimension is not uniform but is complicated, and as a result time and costs required to manufacture the seal portion may be increased.